As a mega fan of sci-fi movies and astronomy I am always confronted with the bitter taste of space ignorance. One of the most common misconceptions–not only in sci-fi movies but also in our pop culture–is about black holes. Ever heard of the phrase “getting sucked into a black hole?”
Newton’s law of gravitation tells us that masses in gravitational fields orbit each other in ellipses, parabolas and hyperbolas. Notice how “sucking” isn’t on this list. So then what would really happen if you were to approach a black hole?
Before we can take this journey through space together, some elements need to be defined for the less nerdy astronomy readers.
Black holes are the remaining cores of massive stars. So, basically a lot of mass squeezed into a tiny space, which results in a strong gravitational pull. The escape velocity is the speed required to leave the orbit of an object. This depends on both the mass and the size of the object. The smaller the size of an object, the stronger the gravitational pull, and as a result a higher escape velocity would be required to leave the orbit.
An artist’s drawing of the black hole Cygnus X-1, pulling in matter from a nearby blue star. (Credits: NASA/CXC/M.Weiss)
So passing by a black hole you wouldn’t get sucked in, unless you were unfortunate enough to get pulled into its gravitational field. The escape velocity would be too high for you to ever be able to escape. In fact the gravitational pull is so strong that not even light can escape a black hole. Thus being given the name “black” hole.
It’s also interesting to note that people outside the black hole would never see you spiraling into the black hole. They would just see you suspended in space, stuck in time. To them, time would stop for you because of the significant increase in the force of gravity. So theoretically if you didn’t vanish from sight, you would never age to the people outside the black hole.
Now that we’ve taken this journey to the great unknown together, we can conclude that black holes don’t go around sucking up moons and stars like some cosmic vacuum.
Until our next journey, live long and prosper.
By: Flora Iranmanesh
Sources:
Bennet; Donahue; Schneider; Voit. The Cosmic Perspective: Stars & Galaxies; Pearson Learning Solutions, Boston, 2015; pp 211-212.
Weiss, M. Cygnus X-1. http://www.nasa.gov/audience/forstudents/k-4/stories/nasa-knows/what-is-a-black-hole-k4.html (accessed Sept 26, 2016). Credits: NASA/CXC/M. Weiss
